Rotary dryers and/or coolers



Jan. 27, 1959 R. R. TEICHMAN 2,87

ROTARY DRYERS AND/OR COOLERS Filed July 18, 1956 4 Sheets-Sheet 1 Jan.27, 1959 R. R. TElCHMiAN 2,870,547

ROTARY DRYERS AND/OR COOLERS Filed July 18, 1956 4 Sheets-Sheet 2 Jan.27, 1959 R. R. TEI CHMAN ROTARY DRYERS AND/GR COQLERS 4 Sheets-Sheet 3Filed July 18, 1956 4 Sheets-Sheet 4 R. R. TEICHMAN ROTARY DRYERS AND/ORCOOLERS Jan. 27, 1959 Filed July 18, 1956 Q \W No v \l I mm 0 mm 0 mm h0 w y v lllw r I h r v bu; l Q. Q i M \w @v @w. I

United States Patent ROTARY DRYERS AND/0R coornns Rudolph R. Teichman,North Riverside, Ill., assignor to Link-Belt Company, a corporation ofIllinois Application July 18, 1956, Serial No. 598,546

6 Claims. (Cl. 34-429) This invention relates to new and usefulimprovements in apparatus for cooling or drying flowable solid materialsand deals more particularly with apparatus of the above type which isespecially adapted for the treatment of very high temperature materialsand for combined drying and cooling operations.

in cooling operations where the temperature of the 2,870,547 PatentedJan. 27, 1959 ice . perature drying medium and which employs a minimummaterial to be treated is very high, considerable difiiculty has beenencountered in the past due to the effect of the heat of the material onthe cooler unit. As a result, such cooler units have been constructed ofspecial, heat resistant materials which are expensive and which aresometimes diflicult to machine or fabricate.

A similar problem has also been presented in drying operations where thenature of the material to be treated is such that it is advantageous touse a drying medium having a very high temperature. Of course, materialsubjected to a high temperature drying medium will have its temperatureincreased sharply as soon as the moisture is removed therefrom. In orderto prevent damage to such material, it is essential that it be removedfrom the dryer as'soon as, or prior to, the time that complete dryinghas been accomplished. In other words, the retention time in suchoperations has been very critical and close control has been required.Further, the material leaving the dryer after having been subjected to ahigh temperature drying medium has often been too hot for subsequentoperations and has required an additional cooling treatment.

In both such operations where very hot material is pubjected to a lowtemperature cooling medium, and where a very wet material-is subjectedto a high temperature drying medium, there has been in the past asubstantial loss of energy and a corresponding reduction in theefficiency of the operation due to the dissipation and loss of heat inthe drying or Cooling medium that is discharged from the unit. Forexample, the heated drying or cooling medium, which could have been usedfor other processing operations such as preheating the combustion airfor kilns, dryers and the like, has been conventionally discharged tothe atmosphere because no inexpensive and efiicient'heat recovery systemhas been available for use in such operations.

A difiiculty encountered in connection with the use of horizontallymounted drum-type dryers, employing internal treatment chambers thatgradually increase in diameter, from the feed end to the discharge end,to effect the axial advancement of the material, has been caused by thepractical limitations that must be imposed on the outside diameters ofsaid dryers, and the dryer lengths that can be employed because of saiddiameter-limitations. In other words, because the diameter of thedischarge end of the gradually increasing internal treatment chambercannot exceed the permissible maximum diameter of the 'dryer drum, theoverall length of the 'dryer and the retention period for the materialthat is provided by such overall length, are both restricted by thepractical limitations that must be imposed on the diameter of the dryer.

amount of special heat resistant materials in its construction.

A further object of the invention is to provide apparatus for coolingvery hot material in such a manner that the heat of the materialwill notdamage the apparatus and only a minimum amount of heat resistantmaterial need be employed in the construction of theapparatus.

Another important object of the invention is to provide a horizontallymounted drum-type drying or cooling apparatus which Will retain thematerial therein for an extended treatment period while the material ismoving continuously through the apparatus.

Other objects and advantages of the invention will be apparent duringthe course of the following description.

In the accompanying drawings forming a part of this specification and inwhich like reference characters are employed to designate like partsthroughout the same,

Figure 1 is a side elevational view of a dryer or cooler embodying theinvention,

Figure 2 is an end elevational view of the device illustrated in Fig. 1,

Figure 3 is a transverse sectional view taken on line 33 of Fig. 1, and

Figure 4 is a fragmentary, longitudinal sectional view of the centerportion of the device illustrated in Fig. 1.

In the drawings, wherein for the purpose of illustration is shown thepreferred embodiment of the invention, and first particularly referringto Fig. 1, reference character 5 designates a horizontally arrangedcylindrical shell of a dryer or cooler that is supported for rotation byconventional tires 6 and trunnions 7 and is rotated by a pinion, notshown, mounted within the housing 8 and engaging a ring gear 9. Thepinion is driven by a motor 10 through a flexible coupling 11 and gearreduction unit 12. The she1l'5 is held against longitudinal movement 'onthe trunnions 7'by thrust rollers 13, see Fig. 4, which arearranged toengage the sides of one or both of the tires 6.

At the feed end of the shell 5, see Figs. 1 and 2, there is provided anannular manifold or distributing ring assembly 14 through which atreatment gas, generally air, is introduced into the shell as will belater described. The manifold 14 is provided with an inlet air connector15 for communication with a suitable source of supply of treatment gas,not shown, and an exhaust air connector 16 for communication with anexhaust duct system, not shown. The entire manifold 14 is mounted in astationary position on supports 17 at its opposite sides and support 13at the bottom of the assembly. A suitable feed chute 19 is provided forintroducing the material to be treated to the interior of the shell 5through the center portion of the manifold 14.

At the opposite end of the shell 5 there is provided a cylindricaldischarge spout 21 which is rigidly mounted on the end wall ZZ-of theshell 5 and projects axially outwardly. Stiifening webs 23 extendbetween and connect the spout 21 and end plate 22 to rigidly maintaintheir axial alignment. 4

A second, larger diametered cylindrical shell 24 is mounted in spaced,axial alignment with the shell 5 and has the spout 21 projecting intoits feed end. The elements for supporting and rotating the shell 24 areidentieal to those emloyed in connection with the shell 5 and have beengiven corresponding reference characters so that a detail description ofthese elements need not be repeated at this time.

At the feed end of the shell 24, see Figs. 1 and 3, there is provided amanifold 25 which is arranged in surrounding relationship with the endportion of th spout 21 that projects into the shell. The manifold isprovided with an inlet air connector 26 for ccrnmu cation with asuitable source of supply of treatment gas such as air, not shown, whichis introduced into e shell through the manifold as will be laterdcscrib. The manifold 25 is also provided with an exhaust connector 27for communication with a suitable exha ct duct system, not shown, forremoving a portion of the treatment gas from within the shell 24, aswill be later described. The entire manifold 25 is mounted in astationary position on supports 28 at its opposite sides and a support29 at the bottom of the assembly.

At the opposite end of the shell 24 there is provided a discharge nozzle31. A discharge hood 32 is mounted to encase the outer end of thedischarge nozzle which projects through an opening in one side of thehood. A seal assembly 33 is provided to prevent the escape of gases fromthe hood 32 around the discharge nozzle 31. At the top of the dischargehood 32 there is provided an outlet connection 34 for communication withan exhaust duct system for the removal of treatment gases from the hood.A discharge spout 35 is provided at the bottom of the hood for releasingfully treated terial therefrom.

Referring now to Figs. 2, 3 and 4 for a brief description of theinternal construction of the two shells 5 and 24, it will be noted thateach has formed therein an annular series of axially extending treatmentgas passages 36 adjacent its inner surface which open radially inwardly.These passages are separated by the axially extending, radial louvres 37that are secured along their outer longitudinal edges to theirassociated shells in any suitable manner. As illustrated in Fig. 4, theradial louvres 37 are longitudinally tapered to gradually decrease theradial dimension of each passage 36 from the feed end to the dischargeend of the associated shell 5 or 24.

Mounted on the inner longitudinal edge portion of each radial louvre 37is a longitudinally extending tangential louvre 33. Each of thetangential louvres 38 has its leading edge portion connected to itsassociated radial louvre 37 and its trailing edge portion overlappingthe leading edge portion of the next successive tangential louvre ininwardly spaced relationship therewith to provide an outlet opening foreach of the treatment passages 36. The cross-sectional configurations ofthe tangential louvres 38 are such that the treatment gas outletsprovided by their overlapped edge portions open rearwardly relative tothe direction of rotation of their shell 5 or 24 so that materialresting on the louvres car not fall into the treatment gas passages 36.

Each of the two shells 5 and 24 and the structure mounted therein isidentical to that which is fully illustrated and described in theapplication for United States Patent, Serial Number 546,092, filed byNorman L. Francis, on November 10, 1955 for Apparatus For Drying andCooling.

Referring now to Figs. 2 and 3, it will be noted that the annularmanifolds 14 and ZSassociated with the shells 5 and 24, respectively,are identical in every respect except that the construction of theexhaust air connector 27 associated with the manifold 25 differs fromthat of the exhaust air connector 16. It will be noted that theconnector 27 spans a smaller exhaust opening through its associatedmanifold 25 than is gas '4 spanned by the connector 16, as will be laterdescribed. For the remaining structure of the two manifolds 1.4 and 25,corresponding reference characters will be applied to the correspondingparts of each and the following description of the manifold 25 isequally applicable to the manifold 14.

Referring now to Figs. 3 and 4, it will be noted that the manifold 25includes concentrically arranged, radially spaced inner and outer rings39 and 41, respectively, which a e sorted in their concentricrelationship by radial wens & extending therebetween. The rings 39- and4-1 are supported in axially aligned relationship with the ring 43carried by the inner edges of the radial louvres 37 at the feed end ofthe shell and with the sh respectively, by the supports 28 and 29.Extending between and mounted on the inner edges of tie two rings 33 and41, to close the spaces formed by the rings and the adjacent ends of theinlet and exhaust openings 5-4 and 45, respectively, are a pair ofbackplates The inlet and exhaust openings 44 and are centered atsubstantially diametrically opposed points on the manifold 25, and itwill be noted that the circumferential dimension of the exhaust opening45 is less than that of the inlet opening for a purpose that will hedescribed in connection with the operation of the device.

An outer seal assembly 48 is provided to close the gap between the outerring 41 and the shell 24 and a similar inner seal assembly 49 isprovided to close the gap between adjacent edges of the inner ring 39and the ring to prevent the escape of treatment gas from between therotating shell 24- and the stationary manifold 25.

The inlet air connector 26 is mounted on the outer edges of the innerand outer rings 39 and 41 in alignment with the inlet opening 44 andprovides an annular connecting flange 51 at its outer end for connectionwith the duct system of a treatment gas supply system, not shown. Theexhaust air connector 27 associated with the manifold 25 is similar inconstruction to the inlet air connector 26 but is smaller and is mountedon the outer edges of the inner and outer rings 69 and 41, respectively,in alignment with the exhaust opening 45. An annular flange 52 isprovided at the outer end of the exhaust air connector 27 for joiningthe connector to the duct work of an exhaust system, not shown.

The exhaust opening 53 of the manifold 14 spans an are which is ofsubstantially greater length than that of the inlet opening 44 andiscentered at a substantially diametrically opposed pointon the manifoldfromsaid inlet opening. The exhaust air connector 16 has an. arcuatelyformed inner sidewall 54 which is aligned with and connected to theinner ring 39; a pair of end plates 55 which are aligned withand'connected .to the radial Webs 42 at the two ends of the exhaustopening 53; and outer side Walls 56 which converge tangentially to theradially outwardly directed outlet opening 57. The front, or outer face,of the exhaust air connector 16 is covered by a plate 58. A similarplate, not shown, covers the rear, or inner face of the connector 16. Aflange 59 surrounds the opening 57 for joining the exhaust air connectorto the duct work of an exhaust system, not shown.

By reference to Figs. 2, 3 and 4, it will be seen that the two shells 5and 24 are each provided with a feed end plate 61 which is mountedinside the ring 43 and is provided with a central opening 62. The feedchute 19 extends through the openingol of the plate 61 associated withthe shell 5 and the discharge spout 21 extends through the opening 62 ofthe plate 61 associated with the shell Mounted on and extending alongthe length of the inner surface of the rotating spout 21 is ascrewconveyor flight 63 by means of which material entering thedischarge spout is advanced into the shell 24.

The apparatus described above operates in the same manner to cool veryhigh temperature materials or to dry wet materials with a very hightemperature treatment gas. The following description of the apparatus,therefore, will be specifically directed to an operation involving thecooling of a high temperature material.

The hot material is introduced into the shell 5 through the feed chute19 while the shell is rotating in a clockwise direction as viewed inFig. 2. This material, after entering the shell 5, will form a bed whichextends longitudinally of the shell and is displaced circumferentiallyfrom the bottom of the shell in the direction of rotation to a positionat which the treatment passages 36 which are aligned with the inletopening 44 lie radially outwardly of the material.

A cooling gas, such as air, at a relatively low temperature isintroduced into the inlet connector for flow into the aligned treatmentgas passages 36 and through the outlets between the tangential louvres38 into contact with the bottom of the bed of hot material throughoutthe length of the shell 5. The cooling treatment gas flowing through thematerial bed in the shell 5 will reduce the temperature of the materialby the transfer of heat to the gas so that the temperaure of the fluidthat has passed radially through the material to the central portion ofthe shell 5 is increased to a relatively high value. The heatedtreatment gas within the central portion of the shell 5 is thereafterremoved from such portion through the treatment passages 36 that arelocated with their outlet openings arranged in the upper portion of theshell and is withdrawn from the treatment passages through the exhaustconnector 16 at the feed end of the shell. Any conventional duct systemwhich is connected to an exhaust fan, or the like, may be connected tothe exhaust connector 16 for transferring the heated treatment gas fromthe dryer to a point of use or discharge to the atmosphere.

As the depth of the bed of material in the shell 5 increases, it willreach a value at which some of the partially cooled material will spillinto the discharge spout 21 and will be moved therealong by the screwconveyor flight 63 and introduced into the shell 24. This axial movementof the material through the shell 5 and the discharge spout 21 iscontinuous and results from the longi tudinal inclined arrangement ofthe tangential louvres 38 within the shell.

The partially cooled material introduced into the shell 24 is againsubjected to the cooling action of a treatment gas which is introducedthrough the inlet connector 26 and which flows through the material intothe centrally located space within the interior of the shell. Since thetemperature of the material entering the shell 24 may still berelatively high, a portion of the cooling gas adjacent the feed end ofthe shell 24 will be increased in temperature by its passage through thematerial bed. A substantial portion of the heated treatment gas may beremoved through the outlets of the treatment gas passages 36 alignedwith the exhaust connector 27 and from such passages into an exhaustduct system which is employed to conduct the heated gas to any suitablepoint of use.

At the discharge end of the shell 24, however, the temperature of thetreatment gas which has passed through the material bed will remain at arelatively low value and this portion of the treatment gas is removedthrough the discharge spout 31 of the shell 24 and through the hood 32and its outlet connection 34 for release in any suitable manner. Sincethe exhaust connector 27 is aligned with an exhaust opening 45 thatspans a relatively small number of treatment gas passages v36, theproportion of the treatment gas withdrawn from the shell 24 through theexhaust connector 27 is limited to a sufficient extent to prevent thewithdrawal of all of the treatment gas within the shell 24.

It will be noted that the use of two separate shells 5 and 24 throughwhich the material continuously passes permits the shell 5, which issubjected to the hottest mate rial, to be smaller in all dimensions thanthe shell 24 so that special, heat resistant materials which arerelatively expensive may be employed in the construction of only theshell 5 and thereby elfect a substantial saving in the total cost of thecomplete installation. Further, it will be seen that substantially allof the gas that has been highly heated in the shell 5, by passingthrough the hottest material, as vwell as a large portion of the gasthat has been heated in the shell 24, by passing through its stillincompletely cooled material, are almost immediately Withdrawn, frompossible further contact with the material, through the treatmentpassages located in the upper portions of the shell, instead of beingcompelled to move concurrently with the material to the discharge end ofthe shell according to common practice. This prompt removal of theheated treatment gas, as soon as it has performed its portion of thematerial cooling operation, prevents the partially cooled material atany given location throughout the lengths of the shells from absorbingadditional heat due to its coming in contact with higher temperaturedgas.

The operating conditions described above are similar to those whichresult from the drying of a wet material with a very high temperaturetreatment gas except that the temperature of the gas is somewhat loweredby its passage through the bed of wet material. The treatment gas,however, will retain suificient heat to make desirable the recovery andsubsequent use thereof by the withdrawal of the gas through the exhaustconnectors 16 and 27. Also, the wet material will be partially driedduring its passage through the shell 5 so that a lower temperaturetreatment gas may be employed in the shell 24 to eliminate thepossibility of damaging the structure of the latter shell.

It is to be understood that the form of this invention herewith shownand described is to be taken as a preferred example of the same, andvarious changes in the shape, size and arrangement of parts may beresorted to without departing from the spirit of theinvention or thescope of the subjoined claims.

Having thus described the invention, I claim:

1. A device of the type defined, comprising first and secondhorizontally arranged cylindrical shells rotatably supported in spacedaxial alignment and each having a feed end and a discharge end, saidfirst shell having its discharge end arranged adjacent the feed end ofthe second shell, a plurality of axially extending louvre assembliesmounted in each shell to form a circumferentially arranged series oftreatment passages with each passage having a rearwardly opening gasoutlet throughout its length and to form a support for a bed ofmaterial, means for supplying material to the feed end of said firstshell, rotating means for receiving material from the discharge end ofsaid first shell and for transferring it to the feed end of said secondshell while restricting the flow of treatment gas from said first shellto said second shell, said 7 2. A device as definedin claim 1 furthercharacterized by said means for receiving material from the dischargeend of said first shell and for transferring itto the feed end of saidsecond shell including a first end plate having a central openingassociated with the discharge end of said first shell, a second endplate having a central opening associated with the feed end of saidsecond shell, a. cylindrical spout extending between said first andsecond.

shells, said spout having its one end connected to said first end platein surrounding relationship with the opening therein and its other endextended through the opening in;

said second end plate so as to protrude into the interior of said secondshell, and means for supporting said spout to relieve said second endplate from the weight thereof.

3. A device as defined in claim Zfurther characterized by saidcylindrical spout having an internal screw conveyor flight extendingalong substantially its entire length and rigidly connected thereto soas to partake of the mo tion of said spout and to push the materialtherethrough, and said supporting means comprising a plurality ofstiffening webs extending between and connected to said spout and tosaid first end plate so as to rigidly maintain said spout in axialalignment.

4. A device of the type defined, comprising first and secondhorizontally arranged cylindrical shells rotatably supported in spacedaxial alignment and each having a feed end and a discharge end, saidfirst shell having its discharge end arranged adjacent the feed end ofthe second shell, a plurality of radial louvres mounted in each shell toprovide an annular series of axially extending treatment passages withinthe shell, a plurality of axially extending tangential louvres supportedon the radial louvres of each shell and having their adjacent edgeportions circumfcrentially overlapped in spaced relationship to provideoutlets for said passages, means for introducing material into the feedend of said first shell to form a bed supported on the tangentiallouvres thereof, a cylindrical discharge spout mounted on the dischargeend of said first shell for rotation therewith and extending in axialalignment with said shells into the feed end of said second shell, meansmounted in said discharge spout for advancing material therein towardthe feed end of said second shell when the spout is rotated and forrestricting the flow of treatment gas from the first shell through thespout, a stationary treatment gas manifold mounted in sealingrelationship with the feed end of each of said shells and having aninlet opening aligned with the passages pcsitioned radially outwardly ofthe location of the bed in the shell for the flow of treatment gasthrough the aligned passages and their outlets through the material 55bed, means associated with each of; said manifoldsfor withdrawing gasfrom the shell through passages'that-are spaced circumferentially fromthe location of said. bed, and means for withdrawing the fully treatedmaterial from the discharge end of said second shell.

5. A device as defined in claim 4 further characterized by each of saidmanifolds having an exhaust opening aligned with passages that arespaced circumferentially from the location of said bed, the manifoldassociated with said first shell having an exhaust opening of sufficientsize to permit the gas withdrawing means associated therewith to exhaustsubstantially all of the treatment gas from the first shell, and themanifold associated with said second shell having an exhaust openingwhich is ofsuch a size that the gas withdrawing meansassociatedtherewith is operable to exhaust a portion only of thetreatment gas from said second shell.

6. A device as defined in claim 4 further charaeterized by the radiallouvres of each shell being longitudinally tapered to support saidtangential louvres in diverging relationship with the axis of the shellfrom the feed end to the discharge end of the shell, the gravitationaleffect of said diverging relationship causing the material to movelongitudinally in each shell toward the discharge end thereof, and saidfirst shell having a diameter less than that of said second shell.

References Cited in the file of this patent UNITED STATES PATENTS2,031,710 lhlefeldt Feb. 25, 1936 2,095,086 Slemmer Oct. 5, 19372,253,098 Schneider Aug. 19, 1941 2,323,289 Anderson et al. July 6, 1943FOREIGN PATENTS 563,293 Great Britain Aug. 8, 1944

